[Problems in ECG studies: evaluation of the low voltage electrocardiogram in the standard and unipolar limb leads].
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004562:Electrocardiography; D005260:Female; D006331:Heart Diseases / Q000175:diagnosis; D006801:Humans; D007223:Infant; D008297:Male; D008722:Methods; D008875:Middle Aged; D012140:Respiratory Tract Diseases / Q000175:diagnosis; D014652:Vascular Diseases / Q000175:diagnosis